1. Field of the Invention
This invention relates to an improved seeker head used with a target pointer/tracker and, more particularly, but not by way of limitation, to an eccentrically driven seeker head for high speed target tracking.
2. Description of Related Art
Heretofore there have been different types of seeker heads, such as AZ/EL and XY mounts. These types of mounts are well known in the art and are used typically on radar in deep space communication or surveillance devices. The AZ/EL mount has a blind spot in the direction perpendicular to the plane of one axis thereby restricting its use as a pointer/tracker for a target seeker. The XY mount avoids the AZ/EL blind spot which is normally directed towards the zenith of earth-mounted systems, by redesigning the axis such that the perpendicularity problem occurs near the earth's horizon. This results in typical keyhole areas for such mounts that prevent full hemispherical coverage.
Gimbal mounts are well known in the art and are designed for fast response. Gimbal locking problems, however, must be avoided. Additionally, a gimbal system is complex and usually too heavy.
A polar mount is a specialized version of an AZ/EL mount but is set to correspond to a latitude in which the device is to be used. This type of mount is not applicable to an application requiring random search orientation. Spinning mass type heads are fast enough to provide tracking information. These heads, however, are complex and are very limited as to field of regard, commonly under +/-8.degree. and are not suitable for use with a large mass.
A pointer/tracker designed by Reinhold, U.S. Pat. No. 4,538,880, provides a high rate of secondary motion and meets the needs of seekers with small heads. This design, however, uses a push/pull set of linear actuators to provide scanning and tracking capabilities. The system is not capable of moving a large mass.
Various mounts designed by the subject inventor, i.e., U.S. Pat. Nos. 4,158,845 and 4,521,782, are well adapted for a seeker requiring rapid head movement through large angles in excess of +/-20.degree.. For small angular motion, such as 1-2.degree. required for target tracking response time, a high speed tracker may be required to provide the secondary motion necessary to accurately measure rates and angles. The subject invention described herein provides the solution to the above-mentioned problems.